JPH1032866A - Position display system for traveling object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit position information for a traveling object to a personal computer by using an internet line and to display it with stored map information on a screen of the personal computer. SOLUTION: GPSs 112 and 212 which are provided to automobiles 110 and 210 respectively measure a position of each automobile 110 and 210. Positional information is transmitted from the GPSs 112 and 212 to a network server 22, via respective radio transmitters 114 and 214 and a radio receiver 20. The server 22 converts the positional information into a packet unit, only when the difference between a measured position P which is included in the positional information and a predicted position X which is calculated, based on positional information that is measured last time excess an enabling error range E. The positional information is transmitted to each of personal computers 126 and 226 via an internet line 24, and the positions of the automobiles 110 and 210 are shown on respective screens 128 and 228 together with stored map information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for distributing position information of a moving object via an Internet line and displaying the information together with map information on a client screen.

[0002]

2. Description of the Related Art In recent years, the Internet has rapidly spread. In data communication on the Internet line, a data exchange method is generally used in which information to be transmitted is temporarily stored in a storage device of a server, and then transmitted according to the availability of a predetermined outgoing line. In this switching method, the use efficiency of the line is high, and various communication processing services such as multi-destination communication can be provided. In addition, in order to transfer and exchange data efficiently, large data is divided into appropriate lengths or combined, control information such as destination is added to each of them, and packets are stored and exchanged in units of these packets. A packet switching method has been implemented.

[0003] In the Internet line, each personal computer is connected to a network server and a client server type, and is independent from the terminal of the main computer, thereby maintaining independence. The network server transmits a packet in response to a request from each personal computer as a client.

[0004] On the other hand, the performance of personal computers tends to be high performance and miniaturized, and it is easy to use precise electronic map information. For this reason, for example, the position information of the object is obtained using a GPS (Global Positioning System), and the position of the object is displayed on the screen together with the map information.

[0005] In the conventional position display system for a moving object, unlike the case of using the Internet line, the position of the moving object is displayed on, for example, a data terminal device subordinately connected to the main computer.

[0006]

SUMMARY OF THE INVENTION In view of the above points, the present invention displays a position of a moving object on a screen of a personal computer storing map information by efficiently utilizing a communication line and accessing position information. It is intended to obtain a display system for a moving object.

[0007]

A position display system for a moving object according to the present invention is provided on the moving object, measuring means for measuring position information including the position of the moving object, and a position obtained by the measuring means. A network server that converts and outputs information in units of packets, and displays the position of the moving object on the screen together with the electronic map information based on the position information in units of packets output from the network server and input via the Internet line. And a client to be provided.

[0008] In the position display system for a moving object, preferably, the output position information output by the network server includes a measurement position at the measurement time and an output position before the measurement time among the position information obtained by the measurement means. The difference between the predicted position predicted from the information and the predicted position exceeds the allowable error range, and the client performs substantially the same position prediction as the prediction performed by the network server, and displays the predicted position on the screen. indicate.

In the position display system for a moving object, preferably, the position information obtained by the measuring means is transmitted to a network server via a wireless transmitter provided on the moving object and a wireless receiver connected to the network server. Transmitted.

[0010] In the position display system of the moving body, preferably, the position information obtained by the measuring means includes the speed at the measurement time of the moving body, and the time at which the position prediction is included in the past measured position information in packet units. And prediction based on the information of the position and the speed.

In the position display system for a moving object, preferably, the position prediction is a prediction based on time and position information included in position information measured in the past.

The network server according to the present invention is provided on a moving body, and measures measuring means for measuring position information including the position of the moving body, and, among the position information obtained by the measuring means, a measuring position at a measuring time. And a position output unit that converts the position information when the difference between the position predicted from the position information output before the measurement time and the predicted position at the measurement time exceeds the allowable error range and converts the position information into packet units and outputs the result. It is characterized in that the position information is output to a client that predicts the position of the moving object in substantially the same manner as the position prediction performed by the network server and displays it on the screen.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a position display system for a moving object according to the present invention will be described with reference to the accompanying drawings. When the force acting on the mass of the moving body is small, the speed of the moving body changes slowly. In the following embodiments, such a situation is assumed.

FIG. 1 is a schematic diagram showing a position display system according to a first embodiment of the present invention. In this case, it is assumed that a car race is performed on a public road. A plurality of vehicles 110 and 210 are provided with GPS as a measuring means.
Radio transmitters 114, 214 having 112, 212 and antennas 116, 216 are provided, respectively. The measured position information is transmitted to each of the wireless transmitters 114 and 21.
4 is sent to the network server 22 from the antennas 116 and 216 via the antenna 18 of the wireless receiver 20.

After processing the location information, the network server 22 transmits the location information to clients, that is, personal computers 126 and 226 via the Internet line 24. Each personal computer 126, 226 stores map information related to the race, and the positions of the cars 110, 210 predicted at predetermined times are displayed on the screens 128, 228 together with the map information.

Hereinafter, this embodiment will be described in detail. G
The PSs 112 and 212 are capable of measuring latitude and longitude, and the position and speed of the cars 110 and 210 and the measurement times thereof are output as position information using the PSs.

The position information by the GPS 112, 212 is:
GPs provided on each vehicle body of automobiles 110 and 210
Wireless transmitters 114 and 214 connected to S112 and 212
Are transmitted as radio signals from the antennas 116 and 216 of FIG. The radio signal is transmitted to the radio receiver 20 via the antenna 18.
Is sent to the network server 22 connected to the wireless receiver 20. The wireless receiver 20 and the network server 22 are connected, but only need to be able to transmit location information, and their physical locations may be far apart,
Also, the connection need not be made by wire.

Next, the processing of the position information in the network server 22 will be described with reference to the flowchart of FIG. The position information obtained by the network server 22 is subjected to data processing and converted into a packet. A packet is a unit of data obtained by dividing a series of information into predetermined lengths and adding control information such as a destination to each of the divided information. Each of the units is called a packet.

The race starts, and each car 11
Position information including the position Po at the time 0 and the position information measurement time 210 and the position Vo and the speed Vo at the time to are received and updated (step S11). Then, this position information is converted into a packet and transmitted on the Internet (step S12).

Next, a measured position P measured at a time t after the transmitted time and a predicted position X at the time t calculated based on the position information at the time to are set (step S13). This predicted position is calculated based on the following expression (1).

X = (t-to) Vo + Po (1) X: predicted position vector at time t t: time to: measurement time included in the packet Vo: velocity vector of the moving object at time too Po: time to Position vector of moving object at

Next, it is checked whether or not the norm of the difference vector between the measured position P and the predicted position X at the time t, that is, the length of the appropriately defined vector is within a predetermined allowable error range E (step S14). ). If the norm is within the predetermined allowable error range E, the position information is not converted into a packet. In this case, the process returns to step S13. On the other hand, when the norm of the difference between the measured position P and the predicted position X at the time t exceeds the predetermined allowable error range E, the process returns to step S11. As long as the norm of the difference between the measured position P and the predicted position X at the time t does not exceed the allowable error range E, the time to, the position Po, and the speed Vo are not updated, and the predicted position X is calculated based on the same measured value. You.

When an error between the predicted position X and the measured value P (hereinafter referred to as a position prediction error) exceeds an error allowable range E, the packet is transmitted by the network server, and the position prediction error is canceled every time the packet is transmitted. It is. That is,
The error between the predicted position X and the measured value P is always suppressed to a certain value E or less. As the growth rate of the position prediction error increases, the frequency of packet transmission increases.

In the linear position prediction according to the equation (1), if the movement of the automobiles 110 and 210 is close to the linear movement at a constant speed, the predicted position X and the measured position P are substantially the same, and the error tolerance E
It takes a long time to cross. Therefore, the flow rate of packets can be reduced. The position prediction is not limited to the linear position prediction. For example, higher-order prediction using higher-order derivatives such as acceleration, or non-linear prediction may be used to improve the prediction accuracy and further reduce the packet delivery frequency.

The network server 22 sequentially processes the position information as described above, and collectively converts the transmitted position information into packets. Each packet includes at least the measurement time and the vehicle 110 at the measurement time.
210 includes position and speed information. The converted packet is transmitted from the network server 22 and transmitted to the personal computers 126 and 226 as clients via the Internet line 24. Note that each of the personal computers 126 and 226 does not need to be connected to the Internet line 24 by a wire, and the installation place is not limited.

In the flowchart of FIG. 2, step S1
In the case of No in No. 4, the network server 22 immediately receives and updates the position information (step S11).
Has shown the procedure for transmitting the packet (step S12). However, the network server can temporarily store the location information in a memory, as is usually done in a server-client type connection. In this case, the network server can transmit a necessary packet according to a request of each personal computer as a client and while checking the availability of a line.

Next, the processing of the position information in each of the personal computers 126 and 226 will be described with reference to the flowchart of FIG. Each personal computer 126, 226 connected to the Internet line 24
Receives packets by communicating with the network server 22. Each of the personal computers 126 and 226 predicts the positions of the automobiles 110 and 210 based on the position information based on the packet based on the equation (1). The calculation method is not limited to the equation (1), but is preferably the same as the calculation method performed by the network server 22.

First, it is checked whether a new packet has arrived (step S21). When a new packet arrives, time to and the position Po and speed Vo at time to are updated based on the position information of the new packet (step S22). When a new packet does not arrive, the time to, the position Po, and the speed Vo remain the position information of the most recently arrived packet. Then, the time to, the position Po, and the speed V, which are updated or are not updated,
The position X at a predetermined time is predicted by o (step S23). Each personal computer 126, 22
6 displays the predicted position X of each car 110, 210 on the respective screens 128, 228 (step S2).
4). Thereafter, the process returns to step S21.

Each personal computer 126, 226
Is provided with electronic map information including a course pre-coordinated, and converts the latitude and longitude of the automobiles 110 and 210 into corresponding points on the electronic map displayed on the respective screens 128 and 228.

As described above, the positions of the cars 110 and 210 are displayed on the screen together with the electronic map. In order to distinguish the cars 110 and 210, the cars 110 and 210 are displayed with graphics having colors and shapes corresponding to the cars 110 and 210, respectively. Further, the figure may be configured by animation. Personal computer 12 connected to the Internet
At 6, 226, it becomes possible to watch this car race. If the position information is stored in the network server or the client, for example, past positions can be displayed in parallel on the screen, or a position at a specific time can be displayed.

Each personal computer 126, 226
Does not need to permanently store the global electronic map information, but it is necessary to at least temporarily store the map information including the course necessary for displaying the screen of the race in some storage device such as a video RAM. is there. Without the electronic map information, the display of latitude and longitude points is an abstract expression lacking in regionality, and it is impossible to grasp the specific situation of the race.

Next, a second embodiment will be described. In this embodiment, the position information only needs to include the measurement time and the position at the measurement time, and the speed is not required. The speed is sent instead of the actual speed instead of the previous and current 2
Position information measurement time to, to 'and measurement position Po, P
The virtual speed Vo 'obtained from o' is used. An example of the simplest calculation method for obtaining the virtual speed Vo 'is shown in equation (2). Other configurations are the same as those of the first embodiment, and a detailed description thereof will not be given here.

Vo ′ = (Po−Po ′) / (to-to ′) (2) Vo ′: virtual velocity vector Po: measured position vector at time to Po Po ′: position of the moving object at time to ′ Vector to: measurement time included in the currently transmitted packet to ': measurement time included in the previously transmitted packet

Generally, there is a deviation between the virtual speed Vo 'and the actual speed Vo. Since this is a speed error, it appears as a growth speed of the error of the predicted position. When the error in the speed is large, the error in the predicted position can be suppressed to a certain value or less, but the growth is fast and the error exceeds the allowable error value E in a short time, so that the packet transmission frequency increases. Equation (2) shows the simplest virtual speed Vo ′ for simplicity of explanation, but in some cases, not only the previous position and time but also the virtual speed extrapolated from past data, such as two times before, etc. Vo '
, The speed error can be reduced and the packet transmission frequency can be suppressed to the same level as in the first embodiment.

In the second embodiment, the linear position is predicted using the virtual speed, but the prediction method is not limited to this. In some cases, higher-order or non-linear position prediction is performed using the measurement time and the measurement position before the time t to improve the prediction accuracy, thereby further reducing the packet transmission frequency.

In the second embodiment, there is no need to measure the speed,
The measuring operation is simplified. Further, the information amount of the packet can be further reduced, and more efficient data transmission becomes possible.

In this embodiment, an automobile race is assumed, but as another example, the present invention can be used for grasping a bus operation situation. In this case, the moving object is each bus, and the position measuring means and the wireless transmitter are attached to the bus. Each bus may be displayed in a different color or graphic for each route. If each client remembers the map information to which the travel route is added,
When individuals need to access the Internet, they can grasp the operation status of each bus.

[0038]

Therefore, according to the present invention, there is provided a moving object display system for displaying a position of a moving object on a screen of a personal computer storing map information by efficiently using a communication line and accessing position information. can get.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of a moving object display system according to the present invention.

FIG. 2 is a flowchart showing a flow of position information processing of a network server in FIG. 1;

FIG. 3 is a flowchart showing a flow of position information processing of the personal computer in FIG. 1;

[Explanation of symbols]

 110, 210 Car 22 Network server 24 Internet line 126, 226 Client 128, 228 Screen

Claims (7)

[Claims] 1. A measuring means provided on a moving body for measuring position information including the position of the moving body, and a network for converting the position information obtained by the measuring means into a packet unit and outputting it to an Internet line. A moving body comprising: a server; and a client that displays a position of the moving body on a screen together with digitized map information based on the position information in packet units input via the Internet line. Location display system. 2. An output position information output from the network server is position predicted from a measurement position at a measurement time and the output position information before the measurement time in the position information obtained by the measurement means. Is a position information when the difference from the predicted position exceeds the allowable error range, and the client performs position prediction substantially the same as the prediction performed by the network server, and displays the predicted position on the screen. The position display system for a moving object according to claim 1, wherein: 3. The method according to claim 1, wherein the position information obtained by the measuring means is transmitted to the network server via a wireless transmitter provided on a mobile body and a wireless receiver connected to the network server. Claim 2
3. A position display system for a moving object according to claim 1. 4. The position information obtained by the measurement means includes a speed of the mobile unit at a measurement time, and a time and position at which the position prediction is included in position information of the packet unit measured in the past. The position display system according to claim 2, wherein the prediction is performed based on information on speed and speed. 5. The position display system according to claim 2, wherein the position prediction is prediction based on time and position information included in the position information measured in the past. 6. A measuring means provided on a moving body for measuring position information including the position of the moving body, a measuring position at a measuring time among the positional information obtained by the measuring means; Position output means for converting and outputting the position information in packet units when the difference between the position information predicted from the previously output position information and the predicted position at the measurement time exceeds an allowable error range, and outputting the packet. A position information transmission system for outputting position information to a client for predicting the position of the moving object by a method substantially the same as the position prediction performed by the network server and displaying the position on a screen, comprising: . 7. A step of measuring position information provided on the moving body and including the position of the moving body, and, among the position information obtained by the measuring means, a measuring position at a measuring time, and a measuring position before the measuring time. Converting the position information in packet units when the difference from the position predicted from the position information output to the predicted position at the measurement time exceeds the permissible error range, and outputting the packet. A position information transmitting method for outputting position information to a client that predicts the position of the moving object by substantially the same method as the position prediction performed by the network server and displays the position on a screen. .